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Method for preparing spongy graphene oxide by using freeze-drying method

A graphene, sponge-like technology, applied in the field of graphene oxide preparation, can solve the problems of hard texture, excessive oxidation, volume reduction, etc., and achieve the effects of small damage, complete peeling, and uniform material distribution

Active Publication Date: 2013-04-24
无锡烯创科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The graphene oxide obtained by drying generally has the problems of shrinking in volume and hardening of texture, and also undergoes denaturation, inactivation, and even excessive oxidation.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Using the improved Hummers method, the raw material is flake graphite. Add 69ml of 98% concentrated sulfuric acid to a dry three-necked flask, place it in an ice bath in ice water, keep the temperature at about 0°C, stir and add 3g of natural flake graphite, 1.5g of NaNO 3 and 9 g KMnO 4 , stirring and reacting for 1.5 hours, controlling the temperature of the water bath in the whole process below 20°C; then raising the temperature of the water bath to 35°C, maintaining this temperature and stirring for 3 hours, then slowly adding 138ml of deionized water dropwise; finally entering the high temperature stage, raising the temperature to 98°C, stir and add 420ml deionized water to dilute, add a certain amount of 5% H 2 o 2 Until no more discoloration; suction filter while hot, fully wash the filter cake with deionized water. The product graphite oxide was obtained.

[0032] The product was dried in an oven at 40°C for 12 hours to obtain dry graphite oxide flakes. Diss...

Embodiment 2

[0034] The improved Hummers method is adopted, and the raw material is artificial graphite. Add 69ml of 98% concentrated sulfuric acid to a dry three-neck flask, place it in ice water and ice bath, keep the temperature at about 0°C, stir and add 3g of artificial graphite, 1.5g of NaNO 3 and 9 g KMnO 4 , stirring and reacting for 10 minutes, and controlling the temperature of the water bath in the whole process below 20°C; then raise the temperature of the water bath to 35°C, keep stirring at this temperature for 1 hour, then slowly add 138ml of deionized water dropwise; finally enter the high temperature stage, and raise the temperature to 98°C, stir and add 420ml deionized water to dilute, add a certain amount of 5% H 2 o 2 Until no more discoloration; suction filter while hot, fully wash the filter cake with deionized water. The product graphite oxide was obtained.

[0035] The product was dried in an oven at 40°C for 12 hours to obtain dry graphite oxide flakes. Dissolv...

Embodiment 3

[0037] The preparation method of graphite oxide is the same as in Example 2 to obtain the product graphite oxide.

[0038] The product was dried in an oven at 40°C for 12 hours to obtain dry graphite oxide flakes. Dissolve 0.1g of graphite oxide flakes in 100ml of deionized water, place in a 40°C water bath and magnetically stir for 20 minutes to obtain a uniformly dispersed graphite oxide aqueous solution. Using a freeze dryer, first lower the temperature of the freezing chamber to -50°C, then put in the graphite oxide aqueous solution, and freeze it for about 1 hour. After it is completely solidified, turn on the vacuum pump to keep the vacuum below 100Pa, and the temperature of the freezing chamber is about -10~ -5°C, keep this state for about 24 hours. The spongy graphene oxide can be obtained by completely sublimating the water, and the porosity of the product is determined to be 90% by the nitrogen adsorption continuous flow method.

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Abstract

The invention relates to a method for preparing spongy graphene oxide by using a freeze-drying method, which is in a loose and porous type and is in a spongy type in a macro-morphology. The method comprises the steps of: after an improved Hummers process is utilized to prepare graphite oxide, preparing graphite oxide into a solution with water or ethanol, and then carrying out quick-freezing and vacuumizing on the solution, and sublimating a solvent to obtain the graphene oxide. The graphene oxide is different from general blocky, film type or powdery graphene oxide. The obtained loose and porous graphene oxide provided by the invention is in a spongy type, is an excellent precursor for preparing graphene, and has a great application foreground in the field of an anti-flaming composite material, an adsorbent and the like. The method for preparing spongy graphene oxide by using a freeze-drying method is free from environmental pollution, convenient in technology and small damage to graphite oxide sheets, and completely strips graphite oxide; and the porosity of the graphene oxide is 20-90% and the pore distribution is uniform.

Description

technical field [0001] The invention belongs to the technical category of graphene preparation and relates to the preparation of spongy graphene oxide with a specific shape. Background technique [0002] Graphene is a research hotspot today. At present, there are many methods for preparing graphene, among which mechanical exfoliation method, chemical vapor deposition method, SiC epitaxial growth method and electrochemical method all have the disadvantages of complex process, low output and high cost. The graphite oxide reduction method, which has the advantages of low cost, large-scale preparation, and simple preparation method, has become a research hotspot. The basic principle of the graphite oxide reduction method is that graphite is first oxidized and exfoliated into graphene oxide, and then reduced to obtain graphene. Among them, oxidizing and exfoliating graphite to obtain graphene oxide is a very critical step, and graphene oxide is an important precursor for prepar...

Claims

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Application Information

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IPC IPC(8): C01B31/04B82Y30/00B82Y40/00C01B32/198
Inventor 王继刚丁滔薛伟江
Owner 无锡烯创科技有限公司
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